1. Field of the Invention
The present invention is directed towards a stabilized trocar, as well as a method of using the same. More particularly, the present invention provides a trocar having a stabilizer positioned adjacent its distal end, wherein the stabilizer, in its deployed position, will prevent premature dislodgement or removal of the trocar cannula from a tissue wall through which it extends.
2. Description of Related Art
Various medical procedures require the penetration of tissue to provide access to the interior of a patient's body. This is particularly true, for example, of endoscopic procedures wherein an opening in tissue must first be created to provide access to anatomical cavities or other internal structures. As used herein, "endoscopic" refers to procedures which employ tubular optical instruments (i.e., endoscopes) which are inserted into a patient to provide vision therein. The endoscope also typically has a hollow central passageway through which other instruments may be inserted into the patient. The term "endoscopic" is generic to, and therefore includes, terms such as "laparoscopic" and "arthroscopic" which refer to the use of an endoscope in a particular region of the body.
Whether the device being inserted into an anatomical cavity of a patient is an endoscope (through which other instruments may thereafter be inserted) or a simple surgical instrument such as a grasper, a cannula is first passed through the tissue wall into the anatomical cavity. Thereafter, the endoscope or other surgical instrument is inserted through the cannula into the anatomical cavity. In this manner, the cannula provides a passageway which will remain open during the surgical procedure, thereby providing the needed access to the anatomical cavity.
One commonly-employed instrument for penetrating tissue and positioning a cannula therein is referred to as a "trocar." Trocars generally comprise a cutting assembly (or obturator) and an outer cannula (also referred to as the trocar tube or sleeve). The cannula is positioned against the patient's skin, and the cutting assembly is positioned within the interior of the cannula. The sharp distal end of the cutting assembly is then urged through the skin until it enters the anatomical cavity being penetrated. The cannula is then urged through the tissue opening created by the cutting assembly, and the cutting assembly is thereafter withdrawn from the cannula. The cannula remains in place, and provides a passageway through which access to the anatomical cavity is provided.
The typical cannula, however, does not include any means for ensuring that the cannula remains in place during the medical procedures. Frequently, the cannula will become dislodged, thereby requiring re-insertion or repositioning. While the cannula may become entirely dislodged such that it falls out of the tissue wall, more often the cannula will only become partially dislodged from the tissue opening such that the tip (or distal end) of the cannula is positioned between tissue layers of the tissue wall through which it extends (rather than within the anatomical cavity). If the surgeon is unaware of this dislodgment, the medical instruments inserted through the cannula may become lost between the tissue layers or even in the wrong anatomical cavity. While usually merely a nuisance to the surgeon, cannula dislodgment can lead to serious patient injury.
Various apparatus and techniques for preventing cannula dislodgment have been developed, including those shown in U.S. Pat. Nos. 5,707,362, 5,407,427, 5,713,869, and 5,725,553. Unfortunately, each of these previous attempts suffers from numerous drawbacks, such as difficulty of operation, ineffectiveness, or even risk of patient injury. Thus, there is a need for apparatus and methods which provide effective cannula stabilization.